Current state of surgical treatment of liver metastases from colorectal cancer

Abstract

Hepatic resection is the procedure of choice for curative treatment of colorectal liver metastases (CLM). Objectives of surgical strategy are low intraoperative blood loss, short liver ischemic times and minor postoperative morbidity and mortality. Blood loss is an independent predictor of mortality and compromises, in common with postoperative complications, long-term outcome after hepatectomy for CLM. The type of liver resection has no impact on the outcome of patients with CLM; wedge resections are not inferior to anatomical resections in terms of tumor clearance, pattern of recurrence or survival. Despite the lack of proof of survival benefit, routine lymphadenectomy has been advocated, allowing the detection of microscopic lymph node metastases and with prognostic value. In experienced hands, minimally invasive liver surgery is safe with acceptable morbidity and mortality and oncological results comparable to open hepatic surgery, but with reduced blood loss and earlier recovery. The European Colorectal Metastases Treatment Group recommended treating up front with chemotherapy for patients with both resectable and unresectable CLM. However, neoadjuvant chemotherapy can induce damage to the remnant liver, dependent on the number of chemotherapy cycles. Therefore, in our opinion, preoperative chemotherapy should be reserved for patients whose CLM are marginally resectable or unresectable. A meta analysis of randomized trials dealing with perioperative chemotherapy for the treatment of resectable CLM demonstrated a benefit of systemic chemotherapy but did not answer the question of whether a neoadjuvant or adjuvant approach should be preferred. Analysis of the literature demonstrates that the results of specialized centers cannot be attained in the reality of comprehensive patient care. Reasons behind the commonly poorer results seen in cancer networks as compared with literature-based data are, on the one hand, geographical disparities in access to specialized surgical and medical care. On the other hand, a selection bias in the reports of the literature may be assumed. Studies of surgical resection for CLM derive almost exclusively from case series generally drawn from large academic centers where patient selection or surgical expertise is superior to what is found in many communities. Therefore, we may conclude that the comprehensive propagation of the standards outlined in this paper constitutes a major task in the near future to reduce the variations in survival of patients with CLM.

Keywords: Liver metastases, Colorectal cancer, Surgery, Chemotherapy, Outcome